Hi, So I know I am comparing apples and oranges with these two. But I recently have been reading alternative money theory and found mutual credit, it is a very old concept and arguably predates barter.
I have no insight how this could be useful for SourceCred, but I found it to a be a powerful concept that others might dig into and find a good use case.
The Wikipedia page for mutual credit is a good first introduction. And then the closest thing we have in terms of applied cryptography is the trustlines project https://trustlines.network/
Again, given that open source is hard to fund, it is possible we might find a work around it if we dig into obscure alternative monetary theories.